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 A000908 Atom-rooted polyenoids with n edges with symmetry class C_s. 0
 0, 0, 1, 4, 14, 47, 164, 565, 1982, 6977, 24850, 89082, 321855, 1169853, 4276923, 15713799, 57998270, 214934984, 799473752, 2983682702, 11169374372, 41929478873, 157807392886, 595340271682, 2250901007539, 8527699269192, 32369066434276 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS S. J. Cyvin, J. Brunvoll, E. Brendsdal, B. N. Cyvin and E. K. Lloyd, Enumeration of polyene hydrocarbons: a complete mathematical solution, J. Chem. Inf. Comput. Sci., 35 (1995) 743-751. S. J. Cyvin, J. Brunvoll, E. Brendsdal, B. N. Cyvin and E. K. Lloyd, Enumeration of polyene hydrocarbons: a complete mathematical solution, J. Chem. Inf. Comput. Sci., 35 (1995) 743-751. [Annotated scanned copy] FORMULA a(n) = A003446(n) - u((n-3)/6) - (u(n/3) + u((n-3)/6))/2 - (u(n/2) + (u((n+1)/2) - u((n-3)/6))) for n > 3 where u(n) = binomial(2*n, n)/(n+1) if n is an integer and 0 otherwise. - Sean A. Irvine, Oct 05 2015 CROSSREFS Cf. A000912, A000913, A000935, A000936, A000941, A000942, A000947, A000948, A000953, A003446, A063786. Sequence in context: A320404 A137284 A228178 * A121095 A264816 A332610 Adjacent sequences:  A000905 A000906 A000907 * A000909 A000910 A000911 KEYWORD nonn AUTHOR E. K. Lloyd (E.K.Lloyd(AT)soton.ac.uk) EXTENSIONS More terms from Sean A. Irvine, Oct 05 2015 STATUS approved

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Last modified January 22 02:46 EST 2022. Contains 350481 sequences. (Running on oeis4.)